Electrical compensator



A. A. TIRRILL.

ELECTRICAL QQM PENSATOR. APPLlCATION,,;l 'F-lj."D AUG.9. 1916.

1,344,742. Patented June 29, 1920.

V- P f f iC/O INVENTOR WITNESSES UNITED STATES PATENT omen.

ALLEN A. TIRRILL, or rrr'rsnuaeri, PENNSYLVANIA, ASSIGNOR 'ro WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION or PENNSYLVANIA.

ELECTRiCAL ooMPn sA'roR.

Specification of Letters Patent. Patented J He 29, 1920.

Application filed August 9, 1916. Serial No. 113,890.

I '0 all tU/LONL it may concern: 1

Be it known that I, ALLEN A. TIRmLL, a citizen of the United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Electrical Compensators, of'which the following is a specification. t I

My invention relates to compensators whereby voltage regulators and other devices may be caused to respond, in their op eration, to the voltage obtaining at a distant point in an electrical distributing circuit.

l/Vhen it is desired to. have a potential reg- I ulator for an electrical generator operate to maintain the voltage at a distant point of the connected circuit substantially uniform,

it is customary to employ a compensator which renders the regulator responsive, in operation, to the voltage obtaining at the distant point. The compensator usually comprises a resistance element and'an inductance element that receive current through a current-transformer. The current is proportional to that traversing the circuit and its value isadjusted' to be approximately in the same ratio as the resistance and inductance of the line. The connections are so arranged that the counterelectromotive forces set up in the resistance and inductance elements serve to reduce the voltage applied to the regulator-winding or windings by an amount proportional to the drop in voltage in the line to the distant point. Y

\Vhen one or several lines are supplied from bus-bars, the current transformer that supplies the resistance and inductance elements of the compensator should be placed where it will be traversed by the total current delivered to the line or lines. However, this is often subject to disadvantages, especially when the voltage of the lines is high, and it is the object "of the-present invention to providecompensating means that may be employed in connection with the low-tension sides of the transformer or transformers that supply high-tension current to the bus-bars to which the several lines are connected, the arrangement being such that the compensation may be substantially correct, irrespective of'the number of transformers and power-distributing lines in use,

In the single-figure of the accompanying drawing, 2 which diagrammatically illustrates a-system embodying my invention, the main circuits are illustrated by single lines for the sake of simplicity, it being understood that the single lines are intended to represent a plurality of conductors nec essarily employed to form an electrical circuit. The system comprises a set of hightension bus-bars 1, from which a plurality of distributing or transmission lines 2, 3, and 4 are supplied and to which high-tension current is supplied through a plurality of banks'of voltage changing-transformers 5, 6 and 7,the primary windings of which are connected to a set of low-tension busbars 8. Switches 9 are employed for selec tively connecting lines 2, 3 and 4 to the high-tension bus-bars 1, and switcheslO and 11 are employed for selectively connecting the transformers 5, 6 and 7 between the high-tension and low-tension busbars. The low-tension bus-bars receive current from one or more generators having armatures 12 and field-magnet windings 13 that receive current from exciter bus-bars 14 and 15. An exciter, having an armature 16 and a field magnet winding 17, supplies current to the bus-bars 14 and 15. The voltage of the exciter is governed by a relay 18 that is adapted to open and close a circuit in shunt to a resistor 19 connected in series with exciter field-magnet winding 17.

The relay 18 is provided with an energizing winding 22 that receives current from the exciter, or from any other suitable source and is'periodically short circuited at 27 for another lever 28 that is provided with an upwardly and laterally extending arm 29 upon which the movable contact, terminal 24 is mounted. The lever 25 is actuated by an electro-magnet having a winding 30 that receives current from the lowtension bus-bars 8'through a transformer 31. In circuit with the winding 30' is a resistor 32 a portion of which isperiodically 7 short circuited by a relay 33 having an energizing winding 34 that is connected in parallel with the relay winding 22. The current flow through the winding 34 is controlled by the contact terminals 23 and 24 in the same manner as that through the winding 22. The engagement and disengagement of he contact members of the relay 38 causes the degree of energization of winding 30 to vary. with the result that the lever 25 is vibrated. and the contact terminal 24 is moved into and out of engagement with the stationary terminal 28.

The lever 28 is actuated by an electromagnet having a winding 36 that receives current from the bus-bars 8 through the transformer 31 and also through two resistors 3? and 38 and two inductive-resistance elements 39 and 40 that constitute parts of the compensator whereby the voltage of the secondary winding of the transformer 31 may be compensated or reduced in proportion to the drop in voltage in the lines 2, 3 and L and in the transformers 5. 6 and 7.

The compensator also comprises currenttransformers 411 and 42 associated with each set of connections between the low-tension bus-bars 8 and the several voltage-changing transformers 5, 6 and 7. Instead of employing two entirely separate and distinct transformers in association with each set of connections, it will, of course, be understood that a single transformer having two secondary windings may be employed. The secondary windings of the transform are connected in parallel with each and to the primary winding 4-3 of a total izing transformer L4. The secondary wind-- ing of the transformer 44f has its terminals connected, respectively, to suitable in the resistor 37 and in the inductii t meat 89. Likewise, the secondary windings of the transformers 42 are connected in parallel with each other and to the primary winding of another totalizing transformer 46. The terminals of the secondary wind ing of the transformer 46 are connected to suitable points in the resistor 38 and in the inductive element 40.

The values of the ohmic and inductive resistances of the devices 37 and 39 are so adjusted as to bear approximately the same ratio to each other as that of the ohmic and inductive resistances of the lines 2, 3 and 4-, and the values of the ohmic and inductive resistances of the devices 2-8 and. il) are so adjusted as to bear approximately the same ratio to each other as that of the ohmic and inductive resistances of the trans formers 5, 6 and 7. The transformation ratios of the transformers 44 and 46 are both adjustable, as, for instance, by the provision of suitable taps in their primary windings and movable switch arms 41-7 and 48 that are adapted to make connections to the taps. WVhen all of the transformers and all of the lines are in use, the switch arms occupy the positions shown, and, when only one transformer and only one line are in use, the arms should occupy positions shown in broken lines. The arm 47 is adjusted to correspond to the number of lines in use and the arm 4l8 to correspond to the number of transformers in use. The movements the arms 47 and 418 may be effected manually, or they may be effected by any suitable means at present available and not constituting part of the present invention. It will be understood that any number of transformers may be used between the low-tension and high-tension bus-bars and, likewise, any number of distributing circuits may be connected to the bus-bars l.

The regulator performs its usual functions and, since, per se, it constitutes no part of the present invention, it is unnecessary to describe its operation in detail. The movable arms 47 and 48 are adjusted in position to correspond, respectively, to the number of lines and to the number of banks of transformers in use, and, when this is done, the current traversing the regulator winding 36 is proportional to the voltage of the bus-bars 8 minus a voltage proportional to the drop in voltage in the trans formers and lines in use. In other words, the voltage inu iressed upon the winding 36 is pro iortional to the voltage obtaining at distant points of the lines 2, 3 and Al, irrespective of the character and size of the loads.

I claim as my invention:

1. In an electrical system, the combination with a plurality of voltage-changing transformers, a plurality of feeder circuits, and selective switching means associated, respectively, with the transformers and the feeder circuits, of current-transforming means associated, respectively with the connections to the voltage-changing transformers and comprising two sets of parallelconnected secondary windings, totalizing transforming means having two primary windings associated, respectively, with the said sets of secondary windings, resistance and inductance elements to which the totalizing transforming means supplies current, and an instrument having a winding the circuit of which includes the said resistance and inductance elements.

2. In an electrical system, the combination with a plurality of volta e-changing transformers, a plurality of feeder circuits, and selective switching means associated, rcspcctively, with the transformers and the feeder circuits, of current-transforming means associated, respectively, with the connections to the voltage-changing transformers and comprising two sets of secondary windings, totalizing transforming means having two primary windings associated,

respectively, with the said sets of seconc'lary windings, resistance and inductance elements to which the totalizing transforming means supplies current, and an instrument having a winding the circuit of which-ineludes the said resistance and inductance elements.

8. In an electrical svstein, the combination with a plurality of voltage-changing transformers, a plurality of feeder circuits, and selective switching means associated, respectively, with the transformers and the feeder circuits, of current-transforming means associated, respectively, with the connections to the voltage-changing transforiners and comprising two sets of secondary windings, resistance and inductance elements to which the said secondary windings deliver current, and an instrument having a winding the circuit of which includes the said resistance and inductance elements.

4. In an electrical system, the combination with a plurality of voltage-changing transformers, a plurality of feeder circuits, and selective switching means associated, respectively, with the transformers and the feeder circuits, of current -transforming means associated, respectively, with the connections to the voltage-changing transformers and comprising two sets of secondary windings, an instrument having a winding, and meansfor developing a counter-electromotive force in circuit with the instrument winding andv supplied with current from said secondary windings.

5. In an electrical system, the combination with two sets of bus-bars, a plurality of voitage-changing transformers, means for connecting the same between the bus-bars, a plurality of feeder circuits, and means for connecting them to one set of the bus-bars,

of current transforming means associated, respectively, with the connections to the voltage-changing transformers and coniprising two sets of parallel-connectedsecondary windings, a variable-ratio totalizing transformer associated with each set of said secondary windings, two'sets of resistance and inductance elements to which the totalizing transformers supply current, and an instrument having a winding the circuit of which "a current transformer inserted in circuit with the connectors to the voltage-changing transformer and comprising two secondary windings, a totalizing transformer having two primary windings associated, respectively, with said two secondary windings,

resistance and inductance elements severally connected to said totalizing transformer windings, and an instrument havin a winding the circuitof which includes the resistance and inductance elements.

7. In an electrical system, the combination with a supply circuit, voltage transformer means and a )luralit of feeder cir cuits connected to the supply circuit to main tain constant voltage conditions on the feeder circuits.

8. In an electrical system, the combination with a supply circuit, a plurality of feeder circuits, a plurality of voltage transformers, and means comprising switches for selectively connecting the feeder circuits through the voltage transformers to the supply circuit, of current-transforming means associated witlisaid connecting means, automatic means controlled by said currenttransforming means for regulating the supply-circuit voltage in accordance with the condition of the feeder circuits, and means for adjusting said automatic'means in accordance with the number of feeder circuits and voltage transformers in circuit.

9. In an electrical system, the combination with a supply circuit, a plurality of feeder circuits, a plurality of voltage transformers, and'means comprising switches for selectively connectingthe feeder circuits through the voltage transformers to the supply circuit, 0f current-transforming means associated with said connecting means, automatic means controlled by said currenttransforniing means for regulating the supply-circuit voltage in accordance with the voltage obtaining at the ends of the selected feeder circuits, and means for adjusting said automatic means in accordance with the number of feeder circuits and voltage transformers in circuit.

10. In an electrical system, the combination with a supply circuit, a plurality of feeder circuits, a plurality of voltage transformers, and means for connecting the.

feeder circuits through the voltage transformers to the supply circuit, of two sets of parallel-connected series transformers associated with said connecting means, and means connected to said current transformers for regulating the, supply-circuit voltage in accordance with feeder-circuit conditions. f

11. In an electrical system, the combination with a supply circuit, a plurality of feeder circuits and means comprising switches for selectively connecting the feeder circuits to the supply circuit, of ourrent-transforming means associated with said connecting means, and means connected tion with a supply circuit, a plurality or "*eder circuits and means comprising swit 10s for selectively connecting the feeder circuits to the supply circuit, of current transforming means associated with said connecting means, and means associated with said currenttransforming means for regulating the supply-circuit voltage in accordance with the condition of the feeder circuits connected to the supply circuit.

13. In an electrical system, the combina' tion with a supply circuit, a plurality of feeder circuits, a plurality of volt age transformers, and means comprising switches for selectively connecting the feeder circuits through said transformers to the supply circuit, of current-transitormer means associated with said connecting means and means connected to the transformer means :for regulating the supplycircuit voltage in accordance with the. condition of the voltage transformers and the condition of the feeder circuits that are connected to he supply circuit.

In testimony whereof, I have hereunto subscribed my name this 21st day of July, 1916.

ALLEN A. TIRRIL'L. 

